Alright, so I'm a BTC whole coiner and have a sizeable amount of Ethereum(not enough to stake though) as well as some XRP.
Diversification is nice if you have enough assets, but especially XRP is imho not worthy for long term hold.
on a HW and I don't plan on selling any into fiat unless I absolutely have to
Make sure you have enough safe copies of the seed and make sure you understand that "when you absolutely have to" sell the crypto prices may also be bad. This means you better think on something else too, unrelated to cypto, you can maybe hold and sell in dark times, even if its price doesn't have so big potential to rise greatly over time.
So gaining interest on coins through providing liquidity through platforms like Blockfi and the like at ~8% at the most is very tempting especially the exponential upside of those gains later on
Now you are getting greedy. I think that Bitcoin rise should be just fine, you should not risk into those. The insurance may cover the fiat value of your funds, with in Bitcoin terms is bad direction.
Next option is using my coins as collateral for a loan to start a business.
The business depends greatly on
you. It's you who have to make sure the business is developing in the correct direction, it is started in the right location,... and you also have all the precautions (including overview on the interviews) to get the right employees. All this can easily lead to many sleepless nights. If you have the material for it, it can be something. I don't have the material, hence I will advise extreme caution. If you go into it, don't go "all in", keep some funds for the case if fails.
I want to use my coins as collateral for a loan to purchase a rental property...
Make sure the property is properly insured
It's not a bad idea overall, but this will mostly bring income to the bank and not you.
And it will be fun to see how can a bank (or similar) handle crypto as collateral.
Imho if you have the guts of a businessman you can do better real estate businesses, where you can actually earn more added value; one would be to buy land around smaller cities (not necessarily in USofA!), hire a proper team and actually build homes. In many countries it can be a better business than a liquor store.
All in all, if you have all it needs to a businessman, you can do better than these ideas. If you don't, you better diversify into safer assets too than crypto (for safer dark days) and wait. With some patience your wealth could grow pretty fast even without unnecessary risks.